ST. PAUL -- Minnesota Department of Health officials on Friday declared an end to the largest measles outbreak since 1990.
The outbreak of spring and summer 2017 that sickened 79 people, mostly children under 10 years of age, began when the first case was identified April 11. The last case was identified on July 13.
Under public health practice, the outbreak can be declared over if there are no new cases identified for 42 days.
The incubation period for measles is 21 days, meaning that’s how long it can take for someone who has been infected with measles to show symptoms. Health officials wait two incubation periods as a cautionary measure.
In that last largest outbreak in 1990, 460 people became ill and 3 people died.
In the 2017 outbreak more than 8,000 people were exposed to measles and 22 people were hospitalized.
Of the 79 cases this year, 70 were in Hennepin County, but there were also three in Ramsey County, four in Crow Wing County in northern Minnesota and two in Le Sueur County in south-central Minnesota.
Minneapolis’ Somali community was hit particularly hard by the outbreak, where 64 of the 79 cases occurred, mostly in unvaccinated individuals. Vaccination rates for measles, mumps and rubella (MMR) vaccine at the start of the outbreak hovered around 42 percent among Somali Minnesotan 2-year-olds. That allowed the virus to spread more easily among children in the community.
“This outbreak showed that preventing disease requires all of us working together,” said Minnesota Health Commissioner Dr. Ed Ehlinger. “Public health is a community, collective endeavor. It’s what we as a society do together to ensure the conditions in which everyone can be healthy.”